DiscussionOur study contributes to a small body of research suggesting that co-rumination may be one gender-linked relationship process that helps explain gender differences in internalizing problems (Calmes & Roberts, 2008; Rose, 2002; Rose et al., 2007; Rose & Rudolph, 2006). We extend this research in important new directions by examining associations with externalizing problems, aspects of peer relations previously neglected, and individual coping skills within a sample of middle adolescents.